The Minneapolis Medial Research Foundation (MMRF) shall be serving as a Special Studies Center (SSCs) for the United States Renal Data System (USRDS), to carry out special studies of significant biomedical importance in the area of Cardiovascular Disease to the Institute and the Nephrology community. The major task of the Special Studies Center for the Cardiovascular Disease in End-Stage Renal Disease (ESRD) is the design and implementation of studies involving the use of existing USRDS data or the collection of new data. The Special Studies Center is responsible for working with the USRDS Coordinating Center, and will provide data to the Government.